package leetcode.editor.cn;

//给你一个由 '1'（陆地）和 '0'（水）组成的的二维网格，请你计算网格中岛屿的数量。
//
// 岛屿总是被水包围，并且每座岛屿只能由水平方向和/或竖直方向上相邻的陆地连接形成。
//
// 此外，你可以假设该网格的四条边均被水包围。
//
//
//
// 示例 1：
//
//
//输入：grid = [
//  ["1","1","1","1","0"],
//  ["1","1","0","1","0"],
//  ["1","1","0","0","0"],
//  ["0","0","0","0","0"]
//]
//输出：1
//
//
// 示例 2：
//
//
//输入：grid = [
//  ["1","1","0","0","0"],
//  ["1","1","0","0","0"],
//  ["0","0","1","0","0"],
//  ["0","0","0","1","1"]
//]
//输出：3
//
//
//
//
// 提示：
//
//
// m == grid.length
// n == grid[i].length
// 1 <= m, n <= 300
// grid[i][j] 的值为 '0' 或 '1'
//
//
// Related Topics 深度优先搜索 广度优先搜索 并查集 数组 矩阵 👍 2511 👎 0

public class IslandNumber{
	public static void main(String[] args) {
		Solution solution = new IslandNumber().new Solution();
		int i = solution.numIslands(new char[][]{{'1', '1', '1', '1', '0'}, {'1', '1', '0', '1', '0'}, {'1', '1', '0', '0', '0'}, {'0', '0', '0', '0', '1'}});
		System.out.println(i);
	}
//leetcode submit region begin(Prohibit modification and deletion)
class Solution {
    public int numIslands(char[][] grid) {
		/**
		 * 1，遍历二维数组
		 * 2，如果当前位置是1，则进行上下左右遍历，找到所有相连的1，并标记为0，
		 * 3，直到上下左右没有1   返回结果并且+1；
		 */
		int n=0;
		for (int i = 0; i < grid.length; i++) {
			for (int j = 0; j < grid[0].length; j++) {
				if(grid[i][j] == '1'){
					island(grid,i,j);
					n++;
				}

			}

		}
		return n;

	}


	private void island(char[][] grid,int i,int j){
		//查询上下左右
		if(i<0||i>=grid.length||j<0||j>=grid[0].length||grid[i][j]=='0'){
			//递归调用结束条件
			return;
		}
		grid[i][j]='0';
		//上面
		island(grid,i-1,j);
		//下
		island(grid,i+1,j);
		//左
		island(grid,i,j-1);
		//右
		island(grid,i,j+1);

	}
}
//leetcode submit region end(Prohibit modification and deletion)

}
